How does population density affects land use in japan?

Due to the population in japan people have suffer many ways, by that i mean that people have been to build up and down they have build underground subways and the subways go down up to three levels and they have also build stores parks and parking lots and even zoos underground So because of population density people who want to own a car have to show proof that they can park it some were off the streets also due to limited space they have also build higher buildings and these building that are higher than normal are earthquake resistance earthquake has a major role in japan people are constantly worried about it and japans get earthquakes daily.also japan had to adopt the method of terracing to make it possible grow local crops

this is what a common entrance to an underground shopping center in japan may look like
people go between different layers of undergrounds buildings to the place they want to go